package main

import (
	"fmt"
	"io"
	"os"
)

func main() {

	file, err := os.Open("aa.txt")

	if err != nil {
		fmt.Println(err)

	}
	defer file.Close()

	file.Seek(4, io.SeekStart)
	bytes := make([]byte, 3)
	file.Read(bytes)
	fmt.Println(string(bytes))
	file.Seek(15, io.SeekCurrent)
	file.Read(bytes)
	fmt.Println(string(bytes))

	file.Seek(-3, io.SeekEnd)
	file.Read(bytes)
	fmt.Println(string(bytes))
}
